Collet



Aipril 24, 1945. A. M. STONER COLLET Filed Sept. 25, 1943 :mmni

Zr! V INVENTOR 71607 A/errzd Jam v ATTORNEY Patented Apr. 24, 1945 UNITED STATES PAT EN T' O F F [C E f COLLET Arthur Merrick Stoner, West Hartford, Conn, as-

s'ignor to The Jacobs Manufacturing Company, 7 Hartford, Conn, a corporation of Connecticut I Application September 23, 1943, Serial No. 503,576

1-0 Claims.

This invention relates to a collet of novel structure which is of simple inexpensive construction and has many advantages over such devices as have been available heretofore.

The object of this invention is to improve upon the devices shown in my Patents Nos. 2,346,706

. and 2,346,707, issued April 18, 1944.

More specifically its object is to provide a collet of the type shown in the aforesaid patents in which the rigid gripping members are inserted in a resilient retainer molded with pool:- ets to receive them, with attendant advantages which will appear in the following specification.

Referring to the drawing:

Fig. 1 is a sectional side elevation of a collet which is made according to and embodies this invention, taken on the line =l--l of Fig. 3;

Fig. 2 is av transverse section of a resilient retainer shown in Fig. 1, the section being taken on the line 2--2 of the latter figure;

Fig. 3 is a transverse section of the collet shown in Fig. 1, the section being taken on the line 3-3 of the latter figure;

comprises a plurality of angularly spaced radially extending ribs 2|, the inner edges of which lie in a. cylindrical surface and the outer edges of which liein frusto-conical surfaces which correspond in angularity to the surfaces M and 15. These ribs, as shown, flare outwardly and have flat sides,

' with the sides of each rib parallel with the proxi- Fig. 4 is a central sectional side elevation "of l tion is a part. This figure is included to. show a way in which the collet disclosed herein may be used;

Fig. 5 is a sectional side elevation of a collet of modified construction which also embodies the present invention;

Fig. 6 is a transverse section of the resilient re tainer which forms a part of the collet shown. in Fig. 5. The section in this figure is taken on the line 6-45 of Fig. 5.

In Figs. 1, 3 and 4, It designates za vc'o'llet which comprises a plurality of gripping member H of rigid material such as hardened steel. As shown in Figs. 1 and 3, the inner edges 12 of the gripping members are straight flat surfaces tangent to a circle concentric with the "axis A-A. One end of the inner edge of each member may be beveled to form a chamber l3.. linth'e particular form illustrated the outer edges are oppositely beveled and when flmshed lie in trusto-conical surfaces 14 and I5. Spaced notches i5, 16 are made in the inner edges of each gripping member to form annular grooves and similar notches l1, l1 alined with the grooves It, It are made in their outer edges. The rear end of the bullet is designated by the reference numeral I8.

20 is a retainer in the form of a body of resilient material, such as oil resistant synthetic rubber, molded to form pockets for receiving and positioning the gripping members. This retainer mate sides of the adjacent ribs and thus form pockets 22 which are parallel with the axis A -A. These pockets are open at their ends and at their outer edges. They are also open at their inner edges except at the parts designated by 23, 23 where the ribs 21 are interconnected byv integral parts of the resilient material which correspond in longitudinal spacing and in cross sectional shape with the notches i6, 16 in the gripping membersi In assembling the collet, the gripping members H are inserted in the pockets 2.2 with their notches l6, l6 engaging the parts 23, 23 of the retainer and then bands 24, 24 of. resilient material are placed around them in the grooves formed by the notches H, H. The diameter of the bands may be the same as that of the grooves formed by the notches l1, ll. or it may be smaller. .In the latter case the bands will be under tension when they are placed around the gripping members. I have shown twmexternal bands 24, 24 alined with the parts 23, '23 of the retainer as this is what I now believe to be a preferred arrangement, but such alinement is obviously unnecessary but the position of the outer bands should be preferably symmetrical in relation to that of the parts 23, 23. A simple modification would be to provide a single outer band intermediate the positions of the parts 23, 23 of the retainer.

In Fig. 4, 30 designates the body of a chuck which has a tapered bore 3| in its rear portion by means of which it may be mounted on a machine tool. In its' forward end is a conical cam surface 32 having an angularity which corresponds to that of the surface 14 of the collet. Between the tapered'bore 3i and the cam surface 32 an internal cylindrical pocket 33 is formed having shoulders 34, 35 which are normal to the axis of the chuck body. 36 is a helical spring in the pocket 33 compressed between the shoulders 34,, 35. The forward part of the body is externally threaded as at 31. 38 is a collar having internal threads which -fit the threads 31. A conical cam surface 39 havingan angularity which corresponds to that of the surface 15 of the c ollet is formed in the forward part of this collar.

As shown in Fig. 4, the spring 36 abutting the inner end l8 of the collet has pushed the latter outwardly so that there is a clearance between the cam surface 32 and the surface M of the collet. The collar 38 has been unscrewed to form a clearance between its cam surface 39 and the surface l of the collet. There is therefore no pressure exerted upon the collet and its elements will be in the relative position in which they are shown in Figs. 1 and 3.

The collet may be tightened onto the shank of a tool or other article placed within it by screwing the collar 38 inwardly on the body 30.

If the bands 24 are under tension the gripping members will be forced inwardly-so that when they are in the at rest position their inner edges will be nearer together than the maxi mum capacity of the collet. Then when the shank of a tool or other article of somewhat greater diameter than the distance between opposite surfaces |2 is pushed into the collet, the gripping members II will be forced outwardly and will hold the, article before the collet is tightened onto it by the chuck in the manner more fully described in my copending application Serial No. 503,575 filed of even date herewith.

In Figs. 5 and 6, a collet NA is shown of modified construction. In this case the gripping mem; bers Il may be like those previously described. 20A designates a retainer in the form of an integral body of resilient material which comprises radially extending outwardly flaring ribs 2 IA interconnected by spaced parts 23A. These form pockets 22A between them which are bridged at parts opposite the parts 23A by parts 25. Orifiees 26 are formed between the parts 23A and 25 through which the g pping members may be inserted. The retainers shown in Figs. 2 and 6 may be molded and vulcanized before the gripping members are inserted. The operation of this device is like that previously described.

The invention herein disclosed may be embodied in collets of various forms, such for exanrple, as those shown in the aforementioned applications, and I intend no limitations other than those imposed by the following claims.

What I claim is:

1. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said openinginterconnecting the ribs, rigid gripping members seated in said pockcentral longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, rigid gripping members seated in said pockets, notches in the inner edges of said members engaging said interconnecting parts, the outer portions of the members extending to a conical surface and arranged to be engaged by said cam surface, and a retaining member surrounding and engaging the gripping members and arranged to hold the members in the pockets.

3. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, flat metallic plates seated in said pockets extending to a conical surface and arranged to be engaged by said cam surface, and a retaining member surrounding and engaging the plates and arranged to hold said plates in the pockets.

4. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, flat metallic plates seated in said pockets, notches in the inner edges of the plates engaging said interconnecting parts, the outer edges of the plates extending to a conical surface and arranged to be engaged by said cam surface, notches in the outer edges of the plates, and a member in the notches in the outer edges of the plates surrounding the plates and arranged to hold said plates in the pockets.

5. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, rigid gripping members seated in said pockets with portions of said members extending to a conical surface and arranged to be engaged by said cam surface, a resilient tension retaining member surrounding and engaging the gripping members and arranged to hold said members in the pockets.

6. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprisin a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, flat metallic plates seated in said pockets, notches in the inner edges of the plates engaging said interconnecting parts, the outer edges of the plates extending to a conical surface and arranged to be engaged by said cam surface, notches in the outer edges of the plates, and a resilient tension member in the notches in the outer edges of the plates surrounding-the plates and arranged to hold said platesin the pockets.

7. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet' comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, and rigid gripping members seated in said pockets with portions of said members extending to a conical surface and. arranged to be engaged by said cam surface, parts of said body forming resilient members bridging the pockets over the gripping members.

8. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening, interconnecting the ribs, and flat metallic plates seated in said pockets extending to a conical surface and arranged to be engaged by said cam surface, parts of said body forming resilient members bridging the pockets over said plates. r

9. A circumferentially continuous machine tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs forming angularly spaced longitudinal pockets, spaced parts projecting outwardly from said opening interconnecting the ribs, and fiat metallic plates, notches in the inner tool collet to be actuated by a cam surface of a chuck, said collet comprising a retainer in the form of a body of resilient material having a central longitudinal opening, a plurality of radially disposed ribs formingangularly spaced longitudinal pockets,spaced parts projecting outwardly from said opening interconnecting the ribs, and flat metallic plates, notches in the inner edges of the plates engaging said interconnecting parts, the outer edges of the plates extending to a conical surface and arranged to be engaged by said cam surface, notches in the outer edges of the plates, parts of said body forming resilient tension members in the notches in the outer edges of the plates bridging the pockets over the plates.

ARTHUR MERRICK STONER. 

